Misfire, Stall, hard to pull away pop & bang

My car has developed a misfire / stalling issue.

When at lights it will often stall.

When pulling away it struggles, I can put my foot on half throttle and nothing will happen then it will come into life an pop and bang from the exhaust.

Its running rough as an bag of spanners and I'm concerned I may not get home!

It's just had new spark plugs and all the wiring checked to the coil packs.

What's next to check?

icv , tps , maf , have you checked for fault codes ?

Inlet hoses, MAF connection? Does the injector (fault) light come on? Do you have a code reader?

Battery connections secure?

Can't believe you have more troubles Gunzi...driven through any standing water/water in electrics?

MM

Air leak?

Thanks chaps food for thought to check over the weekend.

No injector light - it does work as it comes on with ignition on then goes off.

MM I know!! Battery connection is definitely secure

Maybe with the boost working OK and all the testing you've split or blown off a hose, so air leak sounds most likely.

Otherwise the usual suspects as said above, airflow meter, idle control valve or lambda sensor (though it sounds worse than is usually caused by the latter 2).

I’ve had a think about this more and it’s started as a stalling issue with an intermittent hesitation and now it’s all the time, indicative of either a pipe which is split and it’s got worse over time or a pipe which was slightly dislodged by now it’s disconnected.

Pipe watch begins this weekend!

I started to pull the pipes off to check for splits today and naturally snapped the small bit off the inlet hard pipe while trying to lever it off. Will replace it before continuing as I’ve had my fill for now.

Honestly.

Keep the faith Gunzi,

It sounds like its large enough to be pretty obvious. Will be worth it when you have her working properly again and can enjoy her.

Time to consider fitting back a DV at the same time?

MM

Cheers MM I hope so. Joe has showed me a fix for the snapped pipe that I'm going to do this week.

I will sort the problem, then make a compilation video of my love for my Coupe's flutter, before being sensible and putting a DV back on early next year.

I like my Coupes flutter - which is louder since the airbox mod I made lol

If you want an even louder flutter remove the dump valve and blank off the holes

Today I repaired the charge inlet pipe, thanks Joe. I also checked all the remaining pipework from top and underneath and could find no rips tears or loose pipes.

She'll get driven again on Tuesday so will see how it runs before starting on ICV, for which I'll get a new gasket, assuming Fiat still sell them!

What's it showing on the boost gauge at idle, on overrun and on boost? Have you tried with the airflow meter disconnected?

I'll try and get some footage next week Graham. Not run with AFM disconnected yet.

Fingers crossed then Gunzi for a good commute to work tomorrow with no problems!

MM

Cheers MM, I'm hoping the same too. It'd be really nice to be able to enjoy my Coupe without an issues!

OK so yesterdays trip into work was ok, 1 stalling issue at lights, 1 pop 1st thing in the morning and 3-4 pops last thing before I got home.

Today it was a complete nightmare, pop and spluttering all the time, but it got me to work and will get me home, albeit with a fair amount of stress as the issue takes all the enjoyment out of driving.

Before I left this morning I unpluggedg the AFM and it had almost no power to pull away, just all pops and stutters, it was so bad with the AFM unplugged that by the time I got to the end of the road I had to stick the hazards on, pull over and replug the AFM.

I spent a bit of time thinking about the issue and came up with this:

1) Sometimes it drives as normal, no issues
2) Sometimes at part throttle you can be driving along at say 30 mph in 4th at 2k rpm and suddenly it's as if the power goes off, the car begins to slow, even though I've moved my foot off the throttle. The only way to get it to do anything is apply full throttle where it'll pop and stutter and increase in speed again.

Yesterday it was 95% 1), today it was 95% 2).

I visually inspected the pipes insitu at the weekend and found no loose or split pipes, in short of pulling all the pipes off the car are there any other things I should try?

Get Joe to look at it mate.

I spoke to Joe and he offered 2 pieces of advice:

1) clamp off the vacuum assist hose, which I did but the issue remained

2) remove elephant trunk from turbo and blank off with bean tin, then start the car - it should remove the air from all hoses then over 3-4 seconds reinflate, if it's immediate reinflation it should be accompanied by a whistle which would be an air leak. I'll try this on Friday.

Does it improve with engine warmed up or does that make no difference? I still think air leak most likely , but try to get it hooked up to realtime diagnostics to check airflow, lambda, temp sensors etc. to see if anything jumps when the problem happens at idle.

Maybe the new problem was caused by something you did when diagnosing the previous issue... spraying the airflow meter sensor can sometimes damage it , or maybe what you did around the yellow connector is now dodgy.

Not the elephant truck intake pipe Chris, the boost pipe outlet off the turbo, it's the pipe before the SMIC, it's one that looks like a sink U'bend.

Got it, cheers Joe.

Graham it is the same when warm, I suspect you are right and a vacuum test of the boost pipes is planned! Will also check the YCOD wiring.

I had very similar symptoms to this last year. Hunted through every coil pack, injector, electrical connection etc etc.. turned out to be water in the fuel tank. Blocked drain hole and perished seal was letting in just enough water to cause ethanol separation.

The leak might not even be on the intake pipes, could be at the brake boost vacuum line or the injectors or the small bore pipes to boost gauge or valves at rear of engine. Could be just about anywhere so might need a proper smoke test to locate or you could try spraying carb cleaner or use a propane torch (unlit!) around the pipework at idle.

What was the boost gauge showing at idle, overrun and on boost with and without the problem?

OK so at the weekend I removed the outlet pipe on the turbo and bunged it with a glass jar. I then turned the engine on and this sucked all the air out of the pipework and I heard a hiss!

I traced the hiss to a small pipe at the back of the inlet manifold and this was sorted and resealed:


Once this pipe was sorted I retested the system and there was no audible air leak and it too a lot longer to reinflate all the boost pipes, ergo I now know I ahve no air leak between turbo and inlet, and presumably any vacuum assist or other things connected to the inlet manifold.

This morning I drove it again and it was as bad as it was before I found the issue, wanting to stall and backfiring once revs were applied.

A visual inspection on the car has yielded no issues I want to get the 'elephant trunk' inlet pipe removed between air filter and turbo to inspect for cracks.

The boost spools as expected more or less, it seems to have boost but there is very little / inconsistent power, with backfires accompanying what acceleration there is. At idle the boost is on zero, the gauge only reads positive pressure.

I will check the YCOD wiring.

Any comments or suggestions?

Probably air leak between airflow meter and turbo, or the airflow meter itself.

The plastic pipe from the oil separator on back of engine down to the intake just before the turbo goes brittle and can crack, so may even be leaking from anywhere on that hose. Or on one of the small bore hoses (to fuel vapour valve or the EBV) or the plastic joint where those small bore hoses join the intake just before the turbo, I've seen a few of those cracked or broken.

Or maybe leaking where you removed the dump valve?

It doesn't sound like a typical YCOD problem, so I doubt it's that now.

The pipe from oil tank at the back of the engine split years ago and it one side to atoms and inlet side bunged.

I’ll remove the elephant trunk inlet pipe to turn at the weekend and give it and the pipes which join to it a damn good inspection.

As said on the other thread, it'll be sucking in un-metered air through the non-return valve and oil separator tank at idle (and when you lift off at gear change), so that won't be helping.

It's not easy to reach, but for testing you could pull off and block the small bore hose at the top of the non-return valve on the back of the intake manifold , to see how much it helps and if that's the only leak. (Leave the hose attached to the intake side and block the other end where it was attached to the valve).

I will replace the pipe to get it back to OEM set up.

I inspected the 'elephant' inlet pipe at the weekend and found 3 splits in it:

The first photo is the dump valve part which I'm fairly sure I split by overtightening when trying to solve the last problem, as GrahamL predicted!




The second is the oil recirc pipe:



The third one is has a Y pipe stuck in and goes to the EBV:




So I filled with Sugru / putty like solution to plug the holes and drove it this morning and it ran fine. So I am sourcing another pipe and will refit this weekend and hopefully be able to enjoy my Coupe again!!

fingers crossed!

x2 Gunzi! Imagine your forgetting what she feels like running reliably!

Regards

MM

Well I fitted a forge dump valve and replaced the elephants trunk inlet pipe to the turbo and it's still running like a bag of spanners.

https://flic.kr/p/22eX6ci

https://flic.kr/p/FtxTr9

Excuse my neighbour who was chatting to me. This was the only footage where it gave the idling and popping fault, all the other times it would run fine.

Any thoughts before I torch it?

Try what I suggested on the phone with the MAF and let me know how it runs, it's defiantly testing your Coupé passion atm.

The new intake pipe was definitely 100% OK? Did you fix the leak at the oil breather pipe as well?

If so, how does it idle with the airflow meter unplugged? Think I have a spare one I could send you to try.

Also try pulling the cam variator relay and see if it fixes the bad idle.

Don't listen to me, but could there be something foreign "in" the engine, e.g. dropped inside?

Graham
-The replacement intake pipe was ok, I inspected it thoroughly.

-I will test the idle with AFM unplugged, although when I tried to drive it with it unplugged it barely made it to the end of the street under its own steam.

-Where is the cam variator relay?

Joe I will try this over the weekend if it's not pissing it down.

Simon, I think it's unlikely, I've not had anything off in the last few years which would allow something to drop in.

Could a turbo on it's way out cause something like this or would it just smoke like there's no tomorrow?

Silver one at the brake fluid tank. I never really got to the bottom of it but I've had idle issues solved by pulling that relay... the cam variator is engaged at idle and off above idle until high revs, so maybe if the relay is failing and flicking on/off it could cause a bad idle.

It could still be the air leak at the oil breather system if you haven't replaced those pipes yet.

The beaded joiner came without a beaded section so I didn’t install them back into the breather system.

That is a difference as I rerouted the breather pipe so it points up as opposed to down where it was previously.

So I’ll:

Pull the ecu & check chip
Pull the cam variator and replug
Recite breather system when the new joiner arrives

This probably won't be of any help but I took the ecu out of my car the other day, inspected what chip it had in and refitted it. Upon starting the car it ran like a banger, I hadn't touched anything in the engine either

Removed the ecu again and noticed a few green/scabby looking pins, sanded them down as best I could, sprayed some contact cleaner and refitted

Car ran perfectly again, might have been pure coincidence but worth a look

Cheers Adam. I've recently had the ECU out to check for another issue, will see if I reinstalled it correctly.

So this evening I:

Pulled the ecu & check chip
Pulled the cam variator and refitted
Lowered the breather pipe so it points straight down

Will test drive it tomorrow.

You're no idle chap, Chris!

(Sorry, no pun intended )

Ha!

This car may well be the end of me, if I don’t end it first...!

It’s odd on the 5 mikes to work all I got was a slight drop in revs at the lights right outside the building. Onthe way home I had a backfire after a mile, by the time I was near home it was back to low power and constant backfires.

It seems to be linked to the idle, that starts first then the backfires and loss of power?

Chris buy yourself a tin of aerosol brake cleaner and while it's idling spray around the throttle body/ICV and inlet sleeves under the fuel rail, brake cleaner will make it stall if it's drawing in air from where it shouldn't be so worth a try for £2.99.

Will do thanks Joe.